// SPDX-License-Identifier: GPL-2.0
/*
 * Provide a default dump_stack() function for architectures
 * which don't implement their own.
 */
#include <utils/utils.h>
#include <seminix/printk.h>
#include <seminix/init.h>
#include <seminix/smp.h>
#include <seminix/tcb.h>
#include <seminix/uts.h>
#include <seminix/string.h>
#include <seminix/irqflags.h>
#include <seminix/dump_stack.h>

static char dump_stack_arch_desc_str[DEVICE_COMPATIBLE_MAX];

/**
 * dump_stack_set_arch_desc - set arch-specific str to show with task dumps
 * @fmt: printf-style format string
 * @...: arguments for the format string
 *
 * The configured string will be printed right after utsname during task
 * dumps.  Usually used to add arch-specific system identifiers.  If an
 * arch wants to make use of such an ID string, it should initialize this
 * as soon as possible during boot.
 */
void __init dump_stack_set_arch_desc(const char *fmt, ...)
{
    va_list args;

    va_start(args, fmt);
    vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str),
          fmt, args);
    va_end(args);
}

/**
 * dump_stack_print_info - print generic debug info for dump_stack()
 * @log_lvl: log level
 *
 * Arch-specific dump_stack() implementations can use this function to
 * print out the same debug information as the generic dump_stack().
 */
void dump_stack_print_info(const char *log_lvl)
{
    printk("%sCPU: %d Comm: %.20s %s%s %s %.*s\n",
           log_lvl, raw_smp_processor_id(), current->comm,
           "", "", (char *)&utsname.release,
           (int)strcspn(utsname.version, " "),
           utsname.version);

    if (dump_stack_arch_desc_str[0] != '\0')
        printk("%sHardware name: %s\n",
               log_lvl, dump_stack_arch_desc_str);
}

/**
 * show_regs_print_info - print generic debug info for show_regs()
 * @log_lvl: log level
 *
 * show_regs() implementations can use this function to print out generic
 * debug information.
 */
void show_regs_print_info(const char *log_lvl)
{
    dump_stack_print_info(log_lvl);
}

static void __dump_stack(void)
{
    dump_stack_print_info(KERN_DEFAULT);
    show_stack(NULL, NULL);
}

/**
 * dump_stack - dump the current task information and its stack trace
 *
 * Architectures can override this implementation by implementing its own.
 */
#ifdef CONFIG_SMP
static atomic_t dump_lock = ATOMIC_INIT(-1);

asmlinkage __visible void dump_stack(void)
{
    unsigned long flags;
    int was_locked;
    int old;
    int cpu;

    /*
     * Permit this cpu to perform nested stack dumps while serialising
     * against other CPUs
     */
retry:
    local_irq_save(flags);
    cpu = smp_processor_id();
    old = atomic_cmpxchg(&dump_lock, -1, cpu);
    if (old == -1) {
        was_locked = 0;
    } else if (old == cpu) {
        was_locked = 1;
    } else {
        local_irq_restore(flags);
        cpu_relax();
        goto retry;
    }

    __dump_stack();

    if (!was_locked)
        atomic_set(&dump_lock, -1);

    local_irq_restore(flags);
}
#else
asmlinkage __visible void dump_stack(void)
{
	__dump_stack();
}
#endif
